\begin{tikzpicture}

\definecolor{darkgray176}{RGB}{176,176,176}
\definecolor{steelblue31119180}{RGB}{31,119,180}

\begin{axis}[
tick align=outside,
tick pos=left,
x grid style={darkgray176},
xmin=7.121, xmax=7.539,
xtick style={color=black},
y grid style={darkgray176},
ymin=2.88, ymax=9.92,
ytick style={color=black}
]
\path [draw=steelblue31119180, semithick]
(axis cs:7.14,3.2)
--(axis cs:7.14,3.4);

\path [draw=steelblue31119180, semithick]
(axis cs:7.36,3.9)
--(axis cs:7.36,4.9);

\path [draw=steelblue31119180, semithick]
(axis cs:7.47,8)
--(axis cs:7.47,9.6);

\path [draw=steelblue31119180, semithick]
(axis cs:7.52,5.2)
--(axis cs:7.52,5.8);

\addplot [semithick, steelblue31119180]
table {%
7.14 3.3
7.36 4.4
7.47 8.8
7.52 5.5
};
\end{axis}

\end{tikzpicture}
